Mass/charge spectra of secondary ions produced under energetic (similar to MeV/amu) Ar ion impact on gaseous and frozen H2O targets are measured using a magnet-type mass spectrometer. The ion spectra are found to be quite different between these target phases. Multiply charged O-i+ ions with charge states i=2-6, as well as fragmented H+, O+, and OH+ ions, are clearly observed in the gas target, whereas the production of multiply charged ions is strongly suppressed in the frozen target. The most intense ion species is the parent H2O+ ion in the gas target; the H3O+ ion in the frozen target. The most outstanding feature in the frozen target is that the production of cluster ions of the type (H2OH+ (n=1-31), and their intensities, decreasing as the cluster size n increases, show anomalies between n=4 and n=5 and also around n=20, 21, and 22. Negatively charged cluster ions with formula (H2OO- and (H2O)(n)OH- are also efficiently produced in the frozen target.